ugly_number

/*
program to generate nth ugly number


Ugly numbers are numbers whose only prime factors are 2, 3 or 5. The sequence
1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, ...
shows the first 11 ugly numbers. By convention, 1 is included.

*/

# include<stdio.h>
# include<stdlib.h>

/*This function divides a by greatest divisible
  power of b*/
int maxDivide(int a, int b)
{
  while (a%b == 0)
   a = a/b;
  return a;
}

/* Function to check if a number is ugly or not */
int isUgly(int no)
{
  no = maxDivide(no, 2);
  no = maxDivide(no, 3);
  no = maxDivide(no, 5);

  return (no == 1)? 1 : 0;
}

/* Function to get the nth ugly number*/
int getNthUglyNo(int n)
{
  int i = 1;
  int count = 1;   /* ugly number count */

  /*Check for all integers untill ugly count
    becomes n*/
  while (n > count)
  {
    i++;
    if (isUgly(i))
      count++;
  }
  return i;
}

/* Driver program to test above functions */
int main()
{   int n;
    unsigned no;
printf("\nEnter the value for n :");
scanf("%d",&n);

    no=getNthUglyNo(n);
    printf("%dth ugly no. is %d ",n,no);
    getchar();
    return 0;
}